PiPi Combination Flat, Square & Half Round Rolling Mills, 130 mm, Jewelers Tools Features : Gear ratio 4:1, Roller diameter 65 mm, Roller width is 130 mm, Maximum opening 0-5 mm, Flat area (+/- 0.01mm) 57 mm, Square wire (+/- 0.01mm) : 1.0, 2.0, 3.0, 4.0 , 4.5, 5.0, 5.5, 6.0, 6.5, Ring shank - half round ellipsis: 2.5 x 1:3 x 1.25 ; 4 x 1.5. Made from a high quality carbon steel alloy that offers excellent wear resistance and the outer 3mm of the rolls are hardened to around 60 HRC for superior deformation resistance. All powder coated for superior corrosion protection and appearance. Feature true gear reduction with easily turned short handles.